Bone screws with self-tapping threads have been known for decades and constitute key fastening elements in the field of prosthetics. During their long period of use, such bone screws have been the subject of many improvements, both in terms of their materials and their geometric configuration. High-grade steel and titanium screws have enjoyed the most widespread use in the past. However, efforts are continually being made to provide orthopedic implants of different materials with comparable performance characteristics. In this regard, bone screws made of Mg (magnesium) alloys are known (see, e.g., US 2011/0313527 A1), and also screws based on magnesium with special coatings (see, e.g., US 2012/0150295 A1).
Magnesium has lower strength than titanium and high-grade steel. This makes the use of magnesium problematic for self-tapping resorbable bone screws that have to be introduced into bone tissue with high torque. Particularly in the case of small-scale and/or cannulated screws, there is the risk that the torque to be applied will exceed the torsional strength of the material, and that the screw will thus be over-tightened and will break.